Add comment and implementation assertion for proxy condition.go (#9576)

Signed-off-by: Congqi Xia <congqi.xia@zilliz.com>

internal/proxy/condition.go

@@ -23,11 +23,16 @@ type Condition interface {
 	Ctx() context.Context
 }
 
+// make sure interface implementation
+var _ Condition = (*TaskCondition)(nil)
+
+// TaskCondition implements Condition interface for tasks
 type TaskCondition struct {
 	done chan error
 	ctx  context.Context
 }
 
+// WaitToFinish waits until the TaskCondition is notified or context done or canceled
 func (tc *TaskCondition) WaitToFinish() error {
 	for {
 		select {
@@ -39,14 +44,17 @@ func (tc *TaskCondition) WaitToFinish() error {
 	}
 }
 
+// Notify sends a signal into the done channel
 func (tc *TaskCondition) Notify(err error) {
 	tc.done <- err
 }
 
+// Ctx returns internal context
 func (tc *TaskCondition) Ctx() context.Context {
 	return tc.ctx
 }
 
+// NewTaskCondition creates a TaskCondition with provided context
 func NewTaskCondition(ctx context.Context) *TaskCondition {
 	return &TaskCondition{
 		done: make(chan error, 1),